LTE (Long Term Evolution) specifies that a mobile station UE is to execute the following procedure when uplink data to be transmitted occurs (see Non-patent document 1).
In Step 1, the mobile station UE transmits a scheduling request signal to a radio base station eNB.
As illustrated in FIG. 10, if the mobile station UE has a dedicated uplink resource (PUCCH-scheduling request), the mobile station UE transmits a scheduling request signal to the radio base station eNB using the uplink resource.
On the other hand, if the mobile station UE has no dedicated uplink resource, the mobile station UE executes an RA (Random Access) procedure.
In Step 2, the mobile station UE transmits a BSR (Buffer Status Report) to the radio base station eNB.
As illustrated in FIG. 10, the mobile station UE transmits a BSR to the ratio base station eNB via a PUSCH (Physical Uplink Shared Channel) corresponding to a “UL grant” assigned in Step 1.
Note that a “UL grant” is allocated to the mobile station UE by an “RA response” when the RA procedure is executed.
As illustrated in FIG. 11, for each LCG (Logical Channel Group) including an LCH (Logical Channel) in which data to be transmitted is accumulated in a buffer, the mobile station UE is configured to use a BSR to report a total amount of the data accumulated.
In an example of FIG. 11, the mobile station UE reports a total amount of data accumulated in a buffer not for each of LCHs #A to #D but for each of LCGs #0 to #2.
Meanwhile, in LTE Release 12, a study on avoiding radio access network congestion due to U-plane signals is made in the “UPCON (U-Plane Congestion Management) WI (Working Item).”
Lately, services provided even on the same web browser are a mixture of texts, images, motion videos, streaming media, and the like.
Under the above circumstances, if radio access network congestion occurs, there is a demand to transmit streaming media, texts, images, motion videos in this order, for example. In addition to a QCI, the “UPCON WI” defines an “FPI (Flow Priority Indicator)” indicating the priority of each data flow (IP flow) for more detailed priority control, and discusses solving means for (a scheduler of) the radio base station eNB to carry out the QoS control and priority control using the FPI (see Non-patent document 2).